Hieam s



H. s. MAXIM; Brushes for Magneto-Electric Machine.

No.,228,546. Pa tented June 8,1880.

Fig.1. A

.3 H l J a I UNITED STATES PATENT OFFICE.

HIBAM s. MAXIM, or BROOKLYN, ASSIGNOR TO SPENCER D. SOHUYLER,

on NEW YORK, N. Y.

BRUSH FOR MAGNETO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 228,546, dated June 8, 1880.

Application filed October 22, 1875). I

To all whom it may concern:

Be it known that I, HIE-AM S. MAXIM, of the city of Brooklyn, county of Kings, and State of New York, have invented a new and useful Im provement in D yn am o-Magneto-Elee tric Machines, of whichthe following is afull, clear, and. exact description, reference being had to the accompanyingdrawings, which form a part hereof.

My invention relates to that part of the machine known as the commutator brush holder, and it consists in so constructing and arrangiug the parts that the brushes are applied to the commutator with a constant and even pressure readily adjustable to any degree of tension, and are confined in clamps near their extremities, so as to prevent vibration while the machine is in operation, but may readily be advanced when worn away at the ends.

In the drawings, Figure l is a plan of a brush-holder constructed in accordance with my invention. Fig. 2 is a side elevation, and l i 3 is a transverse section, of the same.

Similar letters of reference indicate like parts in each.

A is a rod or bar of non-conducting material, rigidly affixed to the frame of the machine and projectingover the commutator-cylinder.

B is an arm of conductingmaterial, projecting at right angles from the bar A and hung upon it in such a manner that it is free to revolve about it. This arm is made with a longitudinal opening in the end remote from the bar A of Sllli'llGlCllh size to receive the brush 1), made of wire or sheet metal.

C is a cover fitted to the arm B, and H H are set-screws bearing upon the cover O and holding it firmly down upon the brush, as shown in Fig. 3.

E is a clamp rigidly afliXed to the end of the rod A.

At the inside end of the arm B is a projection, K, having a slot operated bya set-screw, L, for receiving the ribbon I of the main circuit.

The spiral spring G is attached at one end to the clamp 15 and at the other to the arm B in such a manner that it tends to press the arm B down upon the commutator, and by varying its tension the brushes may be held against the commutator-plates with any desired degree of pressure.

In commutators as hitherto constructed the brush-holders have usually been rigidly attached to the frame of the machine with some device for adjusting them to different positions with relation to the commutator, in order to secure the proper degree of pressure, and the brushes have been attached in such a way that their spring has served to keep them down upon the commutator cylinder. in

some cases, however, flexible or hinged arms.

have been used; but the brushes have been attached at a point considerably removed from their ends.

It is important that the pressure of the brushes upon the periphery of the commutator should be properly adjusted and constant, as when the pressure is too great the parts are rapidly abraded and worn away, and when it is too slight the opposed surfaces burn and become covered with a black scale, which interferes with their conducting power. It is important also that the brushes should be confined at the end, so as to prevent vibration as much as possible, since such vibration is the source of unpleasant noise when the machine is in operation, and tends to make the brushes jump over bars of the commutator when in rapid movement.

By constructing the brush-holders in the manner above described all irregularity of pressure is obviated, as the arm B automatically adjusts itself to any unevenness of the surface of the connnutator, while all vibration of the brush is prevented by allowing only a small portion to project beyond the arm and screwing the cover 0 firmly down upon it.

As the brush is worn away at the end it may readily be pushed forward from time to time upon turning the set-screws H H until the brush is entirely used up.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In a dynamo-magneto-electric machine, the combination of the hinged spring-arm B with the brush 1), carried in a longitudinal groove or chamber in said arm, and held by a clamp near the outer extremity of said brush, sub stantially as described.

HIRAM S. MAXIM,

Witnesses Guns. 0. OLAeGE'r'r, LEONARD E. CURTIS. 

